Apparatus for polishing and buffing sink ribs



April 26, 1960 E. J. GUINN 2,933,859

APPARATUS FOR POLISHING AND BUFFING SINK RIBS Filed Dec. 1, 1958 4Sheets-Sheet l April 26, 1960 E. .1. GU|NN 2,933,859

APPARATUS FOR POLISHING AND BUFFING sINK ms Filed Dec. l, 1958 4Sheets-Sheet 2 I Erm-cm f/aon I Gw'nn EL@ @mf gw" WWEE April 26, 1960 E.J. GulNN 2,933,859

APPARATusNFoR PoLIsHING AND Bur-FING sINK RIBs Filed Dec. 1, 1958 4Sheets-Sheet 3 Ergjrg- 67 haz-faz? Eldon J Gu/'nn April 26, 1960 E'. J,GUlNN 2,933,859

APPARATUS FOR POLISHING AND BUFFING SINK RIBS Filed nec.` 1, 195s 4sheets-zshaet 4 z L z3/2.a a W Eran-far E/aon J.' Gwnn rotatingiinishing element.

. finishing element.

APPARATUS FR POLISHING AND BUFFHNG SINK REBS Eldon J. Guinu, Detroit,Mich., assigner to Lyon lt1- corporated, Detroit', Mich.,` incorporationof Delaware Application December 1, 19558, Serial No. 777,399 '21Claims. @LS1-92) This invention relates generally to huiiing machinesand more specifically to an improved bufting machine which isparticularly well adapted to polish the dividing rib of a divided sink.Y

Although the principles of the present invention may be included invarious buing machines, a particularly 2,933,859; Patented'Apr. 26, 1960A stillV further object of the present invention is to provide a controlsystem for a nishing machine.

Many other advantages, features and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailedl description and the accompanying sheets ofdrawings in which a preferred structural embodimentl incorporating theprinciples of the'present invention is shown by way of' illustrativeexample.

On the drawings:

Figure 1 is a front perspective view of a nishing machine provided inaccordance with the VprinciplesV of the presentV invention, and shownpartly broken away;

useful application is made in buing or polishing machines of the typethat are employed to polish a combined upwardly and laterally directedsurface, such as the dividing rib of a divided bowl stainlesssteel-.sinkt In particular, when stainless steel-sinks are manufactured,certain tooling marks are produced on the sink, the presence of which ona completed product is unsightly. In order to remove these marks, it isnecessary to iirst polish, and then to buff the surfaces having suchmarks. The'instantinvention may be provided with either a polishing heador a buiiing head, andfor't'nis reason, these terms, insofar as theyapply to the instant invention, are interchangeable, it beingcontemplated that either operation may be performed by this machine.

When either buffing or polishing is to be accomplished, it is desired toobtain a result wherein the polish marks remaining on the product areextremely iinerand uniformly aligned with the direction in which otherpolishing marks disposed on other parts of the sink extend. Thus where arectangular sink has polishing marks along a back or front ledge whichextend inthe principal direction of the sink, the marks which result ona rib transverse to the principal dimension of the sink must betransverse to the rib and thereby parallel with the marks left on thefront and back ledges. Thus to polish the dividing rib of a dividedsink, it is -necessary that the relative movement between the bufling orpolishing element and the dividing rib ofthe sink be in the samedirection as that in which the front and back ledges extend.

sink is supported. The table, in turn, is reciproeably driven up to andagainst a first rotating finishing element,

and then up to and against an oppositely directed second While the tableis reciprocable in a horizontal direction, the iinishing elementspreferably are vertically retractible and extendible so that they do notengage the end ledges of the sink. Controls are provided for theautomatic control, co-ordination or synchronization of the table forthis type of movement, as well as for the finishing elements.

Accordingly, it is an object of the present invention to provide animproved polishing and bufling machine.

Another object of the present invention is to provide a polishing andbuing machine which is particularly well adapted to polish the dividingrib of a divided-bowl sink. t

Yet another object of the present invention is to provide a finishingmachine wherein the workpiece is movably and automatically positionedlwith respect to the Figure V2 is an enlarged perspective view of aportion of Figure 1 with a guard removed and with the finishing elementelevated;

Figure 3 is generally similar to Figure 2 exceptl that the finishingelement has been lowered;

Figure 4 is a perspective schematic diagram of the drive mechanismemployed in the base of Figure 1;

FigureS is a schematic showing of a sink being engaged by a finishingelement;

Figure 6V is a fragmentary elevational view, partly broken away, of anenlarged portion of the front of Figure 1;

Figure 7 is a schematic diagram of the electrical control system of themachine shown in Figure l; and

Figure 8 is a schematic diagram of the pneumatic system of theembodiment of Figure l.

As shown on the drawings The principles of this invention areparticularly useful when embodied in a finishing machine such asillustrated in Figure l, generally indicated by the numeral 10. lThefinishing machine `10 generally includes a base or base assembly ilhaving a workpiece supporting table i2 supported thereon and providedwith means for driving the table 12 along the base 1i, generallyindicated by the numeral i3, together with means responsive to tablemovement for controlling the driving means 13, best illustrated inFigure 7. The finishing machine i@ also includes a pair of supports 14aand 14b on each of which there is rotatably mounted a finishing element15a and 15b, each of which is vertically positionable with respect tothe base 11. The means responsive to table movement for controlling thedriving means 13 also includes means for controlling theverticalposition of theiinishing element 15. l

As best seen in Figure 1, the base l1 includes principally a pair ofbeams 16 which are laterally spaced from each other and which extend ina horizontal direction along thelength of the base 1l. To support thebeams Viti, there is provided a series of vertically extending legs18'rigidly secured to each of the beams i6,

and a series of horizontally extending braces 19, extending.transversely of the beams i6. lf desired, a serles Y of cover plates 2imay be provided to enclose the base 11, being secured to such members asthe beams 16, the Vlegs 18, or the braces 19.

Each of the beams 16 is provided with an upwardly directed surface onwhich there is disposed an elongated track 24 of V-shaped sectionwherein the vertex extends upwardly.

As best seen in Figures 1 and 4, the base 11 is provided with a head.shaft 26 extending transversely of the tracks 24 and supported by a pairof journals 27, 27*

for rotation. At a longitudinally spaced position from the shaft 26, thebase 11 is also provided with a tail shaft29 rotatably carried by avpair of adjustably positioned journals 30, 30 for longitudinalmovementat the opposite or tail end of the base 11. The shaft 29 provided with asprocket wheel 32 disposed intermediate 3 the journals 30 and 30, whilenthe shaft 26 is provided with two sprocket wheels, one wheel 33 beingdisposed intermediate the journals 27, 27, and the other sprocket wheel34 being disposed on one end ofthe shaft 26 outwardly of the journal 27.l

An endless member 35, here comprising a chain, extends about thesprocket wheels 32 and 33 and is tensioned by the position of the tailshaft 29. 1f desired, a pair of guide or idler pulleys or sprocketwheels 36, 37 may also be included to direct the member 35 as required.The member 35 is secured to the table assembly 12, such as by a clamp38'so that a portion of the member 35 is movable with the table 12.

In addition to the rotatably supported endless member 35, the means 13for driving the table 12 along the base I1 also includesa reversiblemotor 39 adjustably secured to the base 11, by means not shown, togetherwith a power train for connecting the motor 39 to the sprocket wheel 34.A crank wheel 17 shown in Figure ll extends through one of the coverpanels 21 for adjustably positioning the motor 39. The power trainincludes a variable pitch pulley 40 secured to the output shaft of themotor 39, which pulley is coupled by a belt 41v to a pulley 42 whichserves as an input to a speed reducer mechanism 43. The speed reducer 43has an output sprocket wheel 44 coupled by a sprocket chain 45 to thesprocket wheel 34. A suitable guard (not shown) may -be employed toenclose the pulleys 40 and 42, and the belt 41.

By positioning the motor 39 selectively, using the hand crank 17, sothat the pulley 40 has a given effective size, the table assembly 12will be driven by the means 13 in a given direction at a substantiallyconstant rate. As the direction of the motor rotation is reversed, thedirection of rotation of the shafts 26 and 29 is also reversed, therebyeffecting table movement in the opposite direction. Thus the tableassembly 12 may be driven toward and along each of the finishingelements 15a and 15b while being supported by the base 11, and may alsobe driven toward the opposite finishing element.

As best seen in Figures 1 and 6, the table assembly 12 includes achassis 47 to which is secured a set of four rollers 48. Each of therollers 48 has an outwardly or axially diverging V-shaped section whichreceives the V-shaped section of the tracks 24. This configurationprevents movement of the table transversely to the tracks 24. To thechassis 47 there is secured a frame or ycradle- 49 for supporting theworkpiece, here shown to comprise a double-bowl sink 20 having adividing rib 22. The cradle 49 functions to support the workpiece 20 sothat it moves with the table 12 along the base 11,' and not transverselythereto.

Asshown in Figure 6, the table assembly 12 is also provided with atleast one actuator element 58 rigidly secured to the chassis 47 forengagement with one or more of a series of switches 61-65. Since theactuating element 58 moves with the table 12, it isapparent that theengagement thereof with the various switches 61-65 is of an intermittentnature, and therefore the switches 61-65 are of a momentary type in atypical embodiment.

Each of the support assemblies 14a and 14b includes a foot 66 whichsupports a movable double slide 67 which in turn supports a column 68.The column 68 may be moved toward and away from the base 11 by movingthe column 68 with respect to the slide 67, and the column 63 may bemoved parallel to the end of the base' 11 by moving the slide 67 withrespect to the foot 66.

As best seen in Figure 2, the column 68 supports a head assembly 69which is vertically positionable thereon by means of a crank 70, and isangularly relatively adjustable with respect to the column 68 by meansof another crank 71. The head 69 is manually positioned when the machineis set up for a given type of workpiece, the adjustments affecting headposition thereafter not being adjusted. The head 69 supports a shaft 72Vwhich is horizontally disposed and which extends par allel to the tablepath. The head 69 also supports a motor 73 which is coupled, as bypulleys and belts 74 to a driven member 75 which is rotatable about theaxis of the shaft 72. The shaft 72 rockably or pivotably supports a yokeshaped arm 76 for angular movement about the axis of the shaft 72. Thefinishing element 15, in turn, is rotatably supported by an end of thearm 76 remote from the shaft 72. To this end, the finishing element 15is provided with a shaft 77 which is rotatably carried by the varm 76,and which is provided with a pulley 78 which is driven through a seriesof belts 79 by the driven member 75.

The position of the motor 73 with respect to the rest of the headassembly 69 is adjustable so that the belt and pulley arrangement 74 ismaintained taut. Similarly, the effective length of the yoke arm 76between the shafts 72 and 77 is also adjustable so that the belts 79 mayalso be kept taut.

The head assembly 69 also supports and includes a uid actuator 80 whichhas a rod 81 which is engageable with arroller 82 carried by the distalend of an extension S3 of the arm 76. Upon extension of the rod 81 asshown in Figure 2, the finishing element 15 is held in the elevatedposition as shown. Upon retraction of the rod 81, as shown in Figure 3,the arm 76 pivots about the shaft 72 so that the shaft 77 moves along anarc in a substantially vertical direction transverse to the path inwhich the table 12 moves, thereby moving the finishing element 15 towardthe path of the table 12.

The arm 76 carrying the finishing element 15 is naturally unbalanced sothat the finishing element 15 is actually lowered by the force ofgravity in this embodiment. It has a total available movement such thatthe periphery of the finishing element 15 may move to a position lowerthan the upper surface of the rib 22 of the sink 20. Thus, when aworkpiece is supported on the table 12, the finishing element 15 mayengage it with a certain force. It can be seen that the actuator 8G andthe arm '76 comprise a part of means for vertically positioning thefinishing element 15 with respect to the table 12. Preferably, a guard85, shown in Figure l, secured to the arm 76 and extending about thefinishing element 15 is also provided.

To position the actuator 80, and hence the finishing element 15, an airsupply 86 is connected to a solenoid actuated spring biased four-wayvalve 87 which communicates with the actuator 80. As best seen in Figure 8, the actuator 80 is a double-acting actuator which optionally isprovided with a spring 88 which serves to raise the finishing element 15in the event that fluid pressure is lost. The four-way valve 87 is alsospringbiased so that if electric power to the valve 87 be lost, thespool thereof will be so moved that fiuid pressure will act to raise thefinishing element 15.

The valve 87, and hence the finishing elements 15a and 15b, and themotor 39, and hence the table 12, are operated by a control circuitwhich includes the switches 61-65. Therefore, the table driving meansand the nishing elements vertical positioning means are under thecontrol of means responsive to table movement.

The switches 61-65 are carried by a rail 89 which is secured to the base11.' Each of the switches may be moved along the rail 89 and clamped inany desired position along the path of table movement.

The control circuit also includes additional switches 50-5'7, 59-60carried by a control panel 95 best seen in Figure 1. The control circuitby which the embodiment shown in Figure l is regulated is shown inFigure 7. The switch 55 is a master switch of the normally closed pushbutton type, the opening of which, even momentarily, shuts down theentire machine. Preferably, this switch includes a reset button 56.

In this embodiment, three-phase power is brought through a circuitbreaker 23 to the motors 73, 73, and

Vphase of each of the motors 73, 73 and 39.

39. Power is also brought through a transformer 25, through appropriatefuses, to the master switch 55' and a main supply line Slt and a returnline 46 between..

which are connected various control circuits.

Each of the motors '73 for rotating the finishing elements 15 isprovided with Ian identical circuit to control the same. Control powerpasses from the master stop switch S through a normally closed Vpushbutton stop switch 5G and 53 respectively. Thence power passes throughthe normally open push button start switches 60 and 5i respectively.Closing of either of the switches 60 and 51 completes a circuit to thecoil 96a and 96h respectively of a relay, which thereby closes to bringpower to each of the motors 73.V For convenience, the various contactsof each relay have been identified with the same numerals as is providedfor the coil of such relay. A pair of thermal overload switches 9'7, 97is included in each of the coil circuits. Closing of each of the relays95 also closes a holding circuit including a contact 9er: which bypassesthe switch et) and a contact lb which bypasses the switch 5d wherebycurrent is maintained through the coils 96 when the momentary pushbutton switches 6l? and 61 are released, respectively. Thus lthe openingof either of the stop switches Sti and 53 interrupts the relay coilcurrent to tie-energize th corresponding motor 73. Likewise opening themaster switch 55 also interrupts the coil current.

Thermal overload switches 84 are provided for each it is to beunderstood that appropriate thermally responsive means, known in theart, are employed with each of the thermal overload switches 97 and 84to actuate the same in response to excessive motor temperatures.

A relay 99 has contacts which connect the motor 3h to the line fordriving the table 12 to the right as shown in Figure l. A relay 1@ hascontacts for connecting the motor 39 to the line for driving the motor39 in the opposite direction, and thereby driving the table to the leftas shown in Figure l. The relays 99 and 100 are mechanicallyinter-connected as indicated by the broken line to preclude simultaneousclosing of the contacts of both relays, and are electricallyinter-connected to prevent energizing of' one relay when the other isclosed. To this end, the coil of the relay El? is connected through apair of norm-ally closed contacts of `the relay 16d while the coil or"the relay tltl is connected thro-ugh a pair of normally closed contactsof the lrelayt. The relays 99 and lili? are commercially available Vas aunitary component employing the mechanical linkage lock and kare knownas reversing starters.

`and tie-energizing the coil of the rel-ay 99. This controlv circuitincludes in series a pair of cycle starting switches 52, 52, a normallyclosed element of the momentary switch 63, the above mentioned normallyclosed oontacts of the relay liti), the coil of the relay 99, and theoverload switches 97, all connected across the lines 31 and fin. it willalso be noted that thisV control circuit may include one or two pairs ofnormally closed relay contacts provided `:for interlocking purposesexplained later herein. However, during the use of the control circuitfo'r the relay coil 99 just described, these contacts are not opened.holding circuit provided which extends across the switches 52, 52 andwhich includes the momentarylimit switch 61 which is normally closed,and a pair of normally open contacts of the relay 99. When the motor 39is being operated by this control circuit, opening of the limit switch61 breaks the holding circuit, thereby causing the motor 39 to stop.This effects a table lmovement stoppage also. In order to prevent anyunwanted coasting, the motor 39 may be provided with a brake 2- arrangedto release the motor whenever it isenergized, and to prevent itsrotation whenever it is tie-energized.

By referring to Figure l, it will be noted that the limit switch 61 isthe middle one of the tive switches 61-65 so that if the cycle startswitches 52 are actuated when the table 12 is at the switch 61 or to theright of it, table movement will take place to the right and the switch61 will not be engaged by vsuch movement. Accordingly, movement'underthis condition to the right will continue until the table12 actuates thenormally closed element vof the limit switch 63 which defines theright-hand extreme selected limit of travel'of the table 12. Since theholding current for the relay 99 is interrupted by the opening of thenormally closed element of the momentary switch 63, further movement tothe right is automatically stopped. Y

A second control circuit for cyclic operation of the motor 39 is alsoconnected across the lines 31 and 45 and includes a pair of normallyopen contacts of 'a first ree versing relay 191, a normally closedelement of the mo'- mentary limit switch 65, the normally closedcontacts of the motor relay 99, the coil of the motor relay 10i), andthe thermal overload switches 97. It can be seen that when the contactsof the relay 101 of this circuit are held closed, the motor 39 willdrive in the opposite direction until the normally closed element in`the limit switch 65 is opened to thereby de-energize the motor 39. lfdesired, this circuit may also include a pair of normally closedcontacts of one or two interlocking relays similar to those mentionedfor the first cyclic control circuit, the purpose of which is to beexplained below. A

To close and to hold closed the contacts of the first reversing relay101 which are in the second control cir-v cuit, there is provided afirst reversing circuit which is energized by an auxiliary supply line90 under the con- It will also be noted that there isa trol of the limitswitch 6l. r[hus the `first reversing cir` cuit includes in series anormallyopen element of the limit switch 63, a pair of normally opencontacts of a relay 103 forming a part of the control circuit forraising and lower ing the finishing element 15b, and the coil of therelay 101, as shown. A holding circuit is also provided which by-passesthe normally open element of the limit switch 63 and the normally opencontacts of the head relay 163, and includes normally open contacts ofthe first reversing relay 101. Thus when table travel toward the right,as

shown in Figure 1, is terminated by the opening of theY normally closedelement of the limit switch 63, there is a simultaneous closing of thenormally open element of the switch 63 which allowscurrent to pass tothe reversing relay 101 provided that the finishing element 15b is in alowered position, indicated by the fact that the normally open contactsof the right head relay 1l3 forming a part of the first reversingcircuit are closed. This momentary closing of the reversing relay 1Malso closes its holding` versing circuit has no eect whatever on therelay 160,

and while the subsequent momentary operation of the limit switch 61breaks the current ow through the holding circuit of the first reversingcircuit, the operation of the motor 39 does not stop because oftheadditional holding circuit provided by the contacts of the relay lili)which span the contacts ofthe rst reversing relay in the second controlcircuit. Thus, as stated above, the second control circuit continues tokeep the relay energized until the normally closed element of the limitswitch 65 is opened to terminate table movement to the left.

To return the table 12 from the left extreme to the center, there isprovided a second reversing circuit including the coil` of a secondreversing relay N2 which may be energizedwhenever the left finishingelement 15a is in a ldownward position, accomplished by the closing ofaseo ond. head relay 104. The second reversing circuit, like the firstreversing circuit, is connected between the auxiliary supply line 90 andthe return line 46 and includes in series a normally open element of themomentary switch 65, and a pair of normally open contacts of the headrelay 104. The second reversing relay 102 is also provided with normallyopen contacts which are connected across the normally open element ofthe momentary switch 65 and the normally open contacts of the head relay104, which relay contacts 102 thereby serve as a holding circuit for thesecond reversing circuit, such holding circuit being under the dominanceof the limit switch 61. The second reversing relay 102 also includes anadditional pair of normally open contacts which are thus held closedwhenever the relay is energized. These additional contacts are connectedacross the holding circuit contacts of the motor relay 99 and therebyform part of a second holding circuit or path including the limit switch61 for closing and holding the rst motor control circuit and -the relay99 closed to return the motor toward a center position. It is apparentthat de-energizing of the head relay 104 will have no effect on thisoperation, and that the opening of the limit switch 61 will break theholding circuit for the motor relay 99 as well as for the secondreversing relay 102.

A pair of additional control circuitsr are provided, connected acrossthe lines 31 and 46, for lowering and raising the finishing elements band 15a respectively. The circuit for controlling the vertical positionof the finishing element 15b includes the valve 87 having a solenoidcoil 87b connected by means of normally open contacts of the relay 103and suitable fuses 91 to the transformer 25. The actuator controlcircuit for the solenoid 87h includes in series a pair of normallyclosed contacts of the relay 100, a normally open element of themomentary switch 62, and a pair of normally open contacts of the relay99, as well as the coil of the relay 103, all connected across the lines31 and 46. It is apparent that this actuator control circuit may beclosed when the table moves to the right from center and closesmomentarily the normally open element of the switch 62, provided ofcourse that the motor relay 99 is energized and that the motor relay 100is not energized. This momentary energizing of the head relay 103 closesa pair of normally open contacts thereof which are connected across thenormally open element of the switch 62 and the normally open contacts ofthe relay 99 as a holding circuit. Thus as the table continues to moveto the right, the relay 103 remains energized, and after the tablemovement has been reversed, the holding circuit has not been broken. Atthe reversal of the motor 39 as described above, the normally closedcontacts of the relay 100 open. Accordingly, there is provided anormally closed element in the momentary switch 62 which is connectedacross these normally closed contacts of the relay 100. Thus upon motorreversal, the normally closed portion of the switch 62 by-passes thenow-open contacts, whereby the holding circuit for the head relay 103 isnot interrupted. However, as the table 12 moves to the left and engagesthe momentary switch 62, the normally closed element thereof ismomentarily opened to break the holding circuit.

It will be noted that a similar structure has been provided for thefinishing element 15a which includes a solenoid 87a which may beenergized by closing of normally open contacts in the relay 104 whichare also energized via the fuses 91. A second actuator circuit forenergizing the coil of the second head relay 104 includes in series, inaddition to such coil, a pair of normally closed contacts of the relay99, a pair of normally open contacts of the relay 100, and a normallyopen element in the momentary switch 64. Provided that the motor relay99 is not energized, and provided that the relay 100 is energized (whichoccurs when the table moves to the left), the table 12 momentarilyengages the momentary switch 64 to momentarily close the normally openelement to complete the second actuator control circuit between thelines 31 and 46. This completion effects closing of the relay 104 whichalso closes a pair of normally open contacts thereof connected acrossthe normally open element of the momentary switch 64 and the now-closedcontacts of the relay 100, to serve as a holding circuit. Similarly, areversal of the table at its left extreme of travel as shown does notbreak the holding circuit but does open the normally closed contacts ofthe motor relay 99. In order to prevent an interruption of currentthrough the holding circuit at this point, a normally closed element ofthe momentary switch 64 is connected across such normally closedcontacts. However, when the table reaches the momentary switch 64 as itmoves toward the center of the `base 11, the normally closed element ofthe switch 64 is momentarily opened to break the holding circuit of thehead relay 104, whereby the solenoid S7 becomes cle-energized and thefinishing element 15a is caused to be moved in an upward direction.

Each of the actuator control circuits which include the relays 103 and104 may also include a pair of normally closed contacts of an additionalrelay, the purpose of which is explained below.

it is apparent that the co-ordinating and synchronizing portion of thecircuit shown in Figure 7 described up to this point in thisspecification enables automatic cycling or sequencing of the variousfunctions described. Thus `a manual closing of lthe start switches 52causes the table to move to the right as shown, causes the finishingelement 15b to be lowered during such movement for engagement with therib 22 of the sink 20, effects a reversal of the table so that a secondfinishing pass is applied -to the workpiece, effects a raising of thefinishing element 15b and subsequently thereto a lowering of thefinishing element 15a which makes a pass on the opposite side of the rib22, effects a table reversal which provides a second pass by thefinishing element 15a, then causes the finishing element 15a to beraised, and after which the table 12 is stopped at a central positionintermediate the finishing elements 15a and 15b.

Naturally, the hand selector wheel 17 is set so that the' motor 39drives the table at the fastest practicable speed. However, this speed,even though it be relatively slow, is ordinarily too fast for set-uppurposes. To that end, an additional manually controllable set ofcontrol circuits is provided so that the cycle above reviewed may becarried out in selected increments. It also permits the cycle to besubstantially varied and reversed at will. Thus, in Figure 7, there isshown an additional set of control circuits which are manuallySelectable and operable, and which in the instant embodiment havebeen'provided in combination with the automatic cycling circuits.

When both types of circuits are included in a single embodiment, it isnecessary that an appropriate means be provided to prevent unwantedinteraction between the two types of circuits. To this end, a selectorswitch 57 has been provided as shown nearthe bottom of Figure 7. Theselector switch is connected to the main supply line 31, and may beselectably positioned neutrally or to supply power to the coil of a leftselector relay 105, or to the coil of a right selector relay 106, eachof which coils is connected to the return line 46. The right selectorrelay 106 has a pair of normally closed contacts in the first motorcontrol circuit located at a point where the original closing current aswell as the holding current must pass therethrough. The selector relay106 also has a pair of normally closed contacts disposed in the secondmotor control circuit located at a point where initial closing currentand any holding current must pass therethrough. The first actuatorcircuit for the right hand relay 103 also includes a pair of normallyclosed contacts of the selector relay 106 loassenso 9 i cated at a pointwhere both'initial closing and holding current must pass therethrough.So long. as the selector switch 57 is not providing power to energizethe selector relay 106, it can thus be seen that each one of the aboveenumerated auto-matic cycling circuits may be employed. However, themoment that thev selector switch 57 is positioned to energize the coilof the selector relay 106,-it can now be seen that the relay 106 willbreak all of such circuits, thereby preventing their being energized, orde-energlzing them as the case may be.

In like manner, the selector relay 105 is provided with normally closedcontacts disposed in the iirst motor circuit for the relay 99, in thesecond motor control circuit for the relay 100, at points wherein theholding circuits for the relays 99 and 100 also pass therethrough, andfor Vthe closing and holding circuits for the leftactuator or head relay104. Thus if the selector switch 57 is positioned to energize the relay105, all such circuits are precluded from being energized, or becomede-energiz'ed.

The selector relays 105 and 106 each also have appropriate normally opencontacts which, upon closing, connect analogous manually operated moto-rcontrol circuits and actuator head relay circuits to the supply line 31.

Thus there is provided a irst manually operable control circuit underthe control of the selector relay 106 for energizing the coil of therelay 09 which includes in series therewith a pair of normally closedcontacts of the rst reversing relay 101, the normally vclosed elementot' the momentary switch 63, apair of normally closed contacts of therelay 100, and a normally open'element of a manually operated momentaryswitch 54. Thus, closing of the manual switch 51tcauses the motor 39 toadvance the table to the right as shown, but since there is no holdingcircuit, release of the switch 54 effects a stoppage of the table. Thismovement may continue until the switch 63 is engaged by the tabletobreak the normally closed element thereof.

In like manner, the device includes a second manually operable controlcircuit for the relay 100 and is connected in series with the coilthereof. This second circuit, under the control of the left selectorrelay 105 includes in series a pair of normally closed contacts f thesecond reversing `relay 102, the normally closed element of themomentary` switch 65, and the normally closed contacts of the motorrelay99, as well as a second normally open element of the manually operablemomentary switch S4. Closing of the switch 54 thus effects tablemovement to the left when the selector switch 57 is positioned toenergize the selector relay 105. Release of the switch 54 again stopsoperation of the vmo-tor 39 j since there is no holding circuit. Thismovement may be continued until the switch 65 is engaged by the table toopen the normally closed element thereof.

The first reversing circuit for the reversing relay 101 also includes apair of normally open relay contacts from the relay 106 which areconnected across the normally open contacts of the head relay 103. 1twill be noted that the reversing circuit is not otherwise under theinlluence'" of the selector relays. Accordingly, when the selectorswitch is positioned to energize the selector relay 106, the firstreversing circuit is placed in an electrical condition wherein it mayperform its reversing function without regard to the position of theheads, as is important during set-up. Thus when the table is manuallymoved to the right to actuate the limit switch 63, not only is tab-lemovement to the right terminated, but the first reversing relay 101becomes energized.V Closingof the lirst reversing relay 101 also closesan additional pair of contacts thereof which are connected across therelay contacts of the relay S and the relay contacts of the relay 102 inthe second manually operable control circuit. The switch Sd being in adepressed position at this moment, an alternate .path is closed forenergizing the motor relay Y100. Thus even though the `selector."v

switch 57 is energizing the relay 106, the table will move to the left.However, when the table reaches the central limit switch 61, the holdingcircuit for the lirst reversing relay 101 is opened whereby furthermovement of the table to the left cannot occur.

Just as the first reversing relay 101 is operative to effect reversal oftable movement toward the finishing element 15b when the selector switch57 is set to the selector relay 106, so is also the second reversingrelay 102'operative to effect a reversal of the table when it is movingtoward the finishing element 15a when the selector switch 57 is set toenergize the selector relay 105. To this end,.the selector relay isprovided with a pair of normally open contacts which by-pass thenormally open contacts of the head relay 104 in the second reversingcircuit which includes the coil of the reversing relay 102. Thus whenthe selector switch 57 is set to energize the selector relay 105 and themanually operable switch 54 is depressed, termination of the leftwardtable movement as shown not only elects the opening of the normally openelement of the limit switch 65, but also effects a closing of the secondreversing circuit including the reversing relay 102, and its holdingcircuit. When the second reversing circuit is thus operated, it islikewise not under any other influence of the selector relays 105 and106. Thus, since the second reversing circuit is also powered by theauxiliary supply line`90, movement of the table to the right from thelinishing element 15a is terminated when the table 12 engages the limitvswitch 61. Of course, it is to be noted that the second reversing relay102 VValso includes an additional pair of normally open contactsconnected to by-pass the normally open contacts of the selector relay106 and the normally closed contacts of the first reversing relay 101whereby current is brought from the supply line 31 by an alternate routeto the remainder of the first manually operable control circuit for themotor relay 99. As is now apparent, a single switch push button of theswitch 54 is thus operative to drive the table in either direction,dependingupon initially the position of the selector switch 57, andsecondarily on whether the corresponding reversing relay has beenactuated.

The selector relay 106 includes a further set of normally open vcontactsforming a part of a manually operable actuator circuit for the finishingelements 15b. This circuit includes in series the normally open contactsof the relay 106, the coil of the head relay 103, and a normally openportion ofa manually operable switch 59. Whenever the switch 59 isclosed, provided the selector switch 57 is energizing the selector relay106, the linishing element 15b is caused to move in a downwarddirection.

There being no holding circuit for the lirst head relay 103 under thiscondition, opening of the manually operable switch 59 'effects a raisingof the lfinishing element 15b.

In like manner, the second head relay 10ft for the finishing element 15ais also provided with a manually opervrable actuator circuit including apair of normally open contacts of the selector relay 105. and a secondnormally open portion of the manually operable switch 59. Thus when theswitch 59 is closed, provided the relay 10S is energized, power isdirected to the coil of the second head relay 4104 which velfectslowering of the head 15a. Likewise, an opening of the switch 59 effectsa raising of the inishing element 15a. Thus it will be noted thatdepending upon the position of the selector switch 57, either one orneither one of the heads will be lowered by actuation of the manuallyoperable switch 59.

While the preferred embodiment includes all of the featuresshown inFigure 7, it is to be understood that advantageous embodiments may 4beconstructed wherein only various selected portions thereof are utilized.

Although various minor modifications might be suggested by those versed`in, the art, it should be understood that I wish to embody within thescope of the patent warranted hereon all such embodiments as reasonablyand properly come within the scope of my contribution to the art.

I claim as my invention:

l. In a finishing machine, the improvement comprising in combinaiton: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said hase, said means including areversible motor; a first relay adapted when closed to drive said motorin a table advancing direction; a second relay adapted when closed todrive said motor in an opposite direction; a third and a fourth relayconnected to supply relay closing power to said first and said secondrelays respectively; and a manual selector switch connected to controlwhich of said third and said fourth relays can be operated.

2. in a finishing machine, the improvement comprising in combination: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a first relay adapted when closed to drive said motorin a table advancing direction; a second relay adapted when closed todrive said motor in an opposite direction; a third relay; a firstcontrol circuit having a normally open manually operated momentaryswitch for closing said first relay; a first holding circuit bypassingsaid manual switch and operative to keep said first relay closed; afirst limit switch having a normally closed element in said firstholding circuit and operative in response to advance of said table toopen said first relay, and having a normally open element simultaneouslyoperative to close a circuit to said third relay; a second controlcircuit responsive to closing of said third relayy for closing saidsecond relay; a second holding circuit bypassing said normally openelement of said first limit switch and operative to keep said thirdrelay closed; and a second limit switch responsive to returning tablemovement and operative to open said second holding circuit to therebyopen said third relay. I

3. In a finishing machine having a finishing element, the improvementcomprising in combination: a workpiece supporting table movablysupported adjacent to thev nshing element; means for driving said tablepast the finishing element, said means including a reversible motor;means for vertically positioning the finishing element with respect tothe path of said table; a first relay adapt'- ed when closed to drivesaidV motor in a table advancing direction; a second relay adapted whenclosed to drive` said motor in a table returning direction; a thirdrelay for controlling said vertical positioning means; a first controlcircuit having a normally open manually operated momentary switch forclosing said first relay; a first holding circuit connected across saidmanual switch and operative to keep said first relay closed; a`firstlimit switch having a normally closed element in said first holdingcircuit and responsive to advancement of said table and operative toopen said first relay; a second con' trol circuit responsive tooperation of a normally open element in said first limit switch forclosing said second relay; a second holding circuit connected acrosssaid normally open element of said first limit switch and operative tokeep said second relay closed; a third control circuit having a normallyopen momentary switch responsive to table advancement and operative toposition said third relay to be operative on said vertical positioningmeans to effect movement of the finishing element toward the path ofsaid table; a third holding circuit connected across said normally openmomentary switch of said third control circuit and operative to keepsaid third relay closed; a normally closed momentary switch in saidthird holding circuit responsive to returning table movement andoperative to position said third relay to be operative on said verticalpositioning means to effect movement of the finishing element away fromthe path of said table; and

a second limit switch comprising a part of saidsecond holding circuitand responsive to further table movement and operative to open saidsecond holding circuit.

4. In a finishing machine, the improvement comprising in combination: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a first relay adapted when closed to drive said motorand hence said table in a first direction; a second relay adapted whenclosed to drive said motor and hence said table in an oppositedirection; a third relay; a main electrical supply line and a returnline; a first control circuit, including in series a normally openmanually operated momentary switch, a normally closed element of a firstlimit switch responsive to movement of said table, and the coil of saidfirst relay, connected across said lines; a first holding circuitbypassing said manual switch and operative to keep said first relayclosed; a second control circuit, including in series a pair of normallyopen contacts of said third relay and the coil of said second relay,connected across said lines; a third control circuit, including inseries a normally open element of said first limit switch and the coilof said third relay, connected to said return line; a second holdingcircuit bypassing said normally open element and operative to keep saidthird relay closed; and a second normally closed limit switch responsiveto table movement connecting said supply line to said first holdingcircuit, said third control circuit, and said second holding circuit.

5 In a finishing machine, the improvement comprising in combination: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a first motor relay adapted when closed to drive saidmotor and hence said table in a first direction; a second motor relayadapted when closed to drive said motor and hence said table in anopposite direction; a first reversing relay; a second reversing relay; amain electrical supply line and a return line; a first control circuit,including a normally open manually operated momentary switch, a normallyclosed element of a first momentary limit switch responsive to tablemovement, and the coil of said first motor relay, connected in seriesacross said lines; a

first holding circuit bypassing said manual switch and operative to keepsaid first motor relay closed; a second control circuit, including apair of normally open contacts of said third relay, a normally closedelement of a second momentary limit switch responsive to table movement,and the coil of said second motor relay, connected' in series acrosssaid lines; a first reversing circuit, including in series a normallyopen element of said first limit switch and the coil of said firstreversing relay, connected to said return line; a second holding circuitbypassing said normally open element of said first limit switch and operative to keep said first reversing relay closed; a second reversingcircuit, including in series a normally open element of said secondlimit switch and the coil of said second reversing relay, connected tosaid return line; a third holding circuit bypassing said normally openelement of said second limit switch and operative to keep said secondreversing relay closed; a fourth holding circuit including contacts ofsaid second reversing relay connected across said first holding circuit;and a third normally closed limit switch responsive to table movementconnecting said supply line to each of said four holding circuits andsaid two reversing circuits.

' 6. In a finishing machine, the improvement comprising in combination:a base; a workpiece supporting table movably carried by said base; meansfor driving said tabie along said base, said means including areversible motor; a first motor relay adapted when closed to drive saidmotor and hence said table in a first direction; a second motor relayadapted when closed to drive said motor and hence said table in anopposite direction; a first reversing relay; a second reversing relay; amain electrical supply line and a return line; a first controllasse-,85a

. 13 circuit, including a rst normally open element of a manuallyoperable momentary switch, a pair of normally closed contacts of saidfirst reversing relay, the coil of said rst motor relay, and a normallyclosed element of a first momentary -lirnit switch responsive to tablemovement, connected in series across said lines; a second controlcircuit, including a second normally open element of said manuallyoperable momentary switch, a pair of normally closed contacts of saidsecond reversing relay, the coil of said second motor relay, and anormally closed element of a second momentary limit switch responsive totable movement, connected in series across said lines; a lirst reversingcircuit, including in series a normally open element of said first limitswitch and the coil of said first reversing relay, connected to saidreturn line; a first holding circuit bypassing said normally openelement of said first limit switch and operative t'o keep said firstreversing relay closed; a second reversing circuit, including in seriesa normally open element of said second limit switch and the coil of saidsecond reversing relay, connected to said return line; a second holdingcircuit bypassing said normally open element of said second limit switchand operative to keep said second reversing relay closed; said firstreversing relay having a pair of normally open contacts connected acrosssaid normally closed contacts of said second control circuit; saidsecond reversing relay having a pair of normally 'open contactsconnected across said normally closed contactsrrof said first controlcircuit; and a third normally closed limit switch responsive to tablemovement connecting said .supply line to Aeach of said holding andreversing circuits.

7. In a finishing machine, the improvement comprising i-n combination: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversibley motor;

a first motor relay adapted when closed to drive said motor and hencesaid table in a first direction; a second motor relay adapted whenclosed to drive said motor and hence said table in an oppositedirection; a first reversing relay; a second reversingy relay; a mainelectrical supply line and a return line; a first manually energizablecontrol circuit, responsive to movement of said table, connected acrosssaid lines `for operating said first control relay and said firstreversing relay; a second control circuit energizable by said firstreversing relay, responsive to movement of said table in the oppositedirection, and connected across said lines for operating said secondcontrol relay and said second reversing relay; said first controlcircuit being energizable also by said second reversing relay; and alimit switch responsive to table movement and operative on at least oneo-f said control circuits to stop movement of said table at a generallycentral position along said base.

8. In a finishing machine, the improvement compris.- ing in combination:a base; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a first motor relay adapted when closed to drive Vsaidmotor and yhence said table in a first direction; a

second motor relay adapted when closed to drive said motor and hencesaid table in an opposite direction; a

rst reversing relay; a second reversing relay; a main.

electrical supply line and a return line; aY first manually energizablecontrol circuit under the control of said reversing relays, including afirst limit switch responsive to movement of said table, said circuitbeing connected across said lines for operating said first control relayand one of said reversing relays; a second control circuit -manuallyenergizable under the control of said reversing relays, including asecond Vlimit switch responsive to opposite movement of said table, saidcircuit being connected across said lines for operating said secondcontrol relay and the other of said reversing relays; whereby when saidfirst control circuit is manually energized, said limit switch, andlwhen said second control circuit Vis,

manually energized, said table is driven toward said second limitswitch, and upon engaging said second limit;

switch is driven toward said first limit switch.

9. ln a finishing machine, the improvement comprising in combination: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a first motor relay adapted when closed to drive saidmotor and hence said table in Ya first direction; a second motor relayadapted when closed to drive said motor and hence said table in anopposite direction; a first reversing relay; a `second reversing relay;a main electrical supply line and a return line; a pair of firstmanually energizable control circuits having a common portion, includinga first limit switch in said portion responsive to movement of said`table, said circuits being connected across said lines for operatingsaid first controlrrelay and one of said reversing relays; a pair ofsecond control circuits having a common portion, including a secondlimit switch in said portion responsive to opposite movement of saidtable, said circuits being connected across said lines for operatingsaid second control relay and the other of said reversing relays, one ofsaid second control circuits being manually energizable under thecontrol o said reversing relays, and the other of said second controlcircuits being energizable by said one reversing relay; a selectorcircuit operative to select one of said first circuits and said one ofsaid'second control circuits for manually controlled table movement, andthe other of said first circuits and said other of said second controlcircuits for automatically controlled table movement; and a third limitswitch dis-v posed intermediate said first and second limit switches andcomprising a part of said other first circuit for terminating saidautomatically controlled table movement.

l0. In av finishing machine, the improvement comprising in combination:a base; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a rst motor relay adapted when closed to drive saidmotor and hence said table in a first direction; a second motor relayadapted when closed to drive said motor and hence said table in anopposite direction; a. reversing relay;` a main electrical supply lineand a return line; a first control circuit, including `a first normallyopen element of a manually operable momentary switch, a pair of normallyclosed contacts of said reversing relay, the coil 'of said first motorrelay, and a normally vclosed element of a first momentary limit switchresponsive to table movement, connected in series across 'said lines; aY

second control circuit, including a second normally open element of saidmanually operable momentary switch, a pair of normally open contacts ofsaid reversing relay, the coil of said second motor relay, and anormally closed element of a second momentary limit switch responsive totable movement, connected in series across said lines; a reversingcircuit, including in series a noi'- nially open element of said firstlimit switch and ther coil of said reversng relay, connected to saidreturn line; a holding circuit bypassing said normally open element ofsaid first limit switch andjoperative to keep said reversing relayclosed; and a third normally closed limit switch responsive to tablemovement connecting said supply line to said reversing and holdingcircuits.` v

ll. ln a finishing machine, the improvement comprising in combination: abase; a workpiece supporting table movablv carried by said base; meansfor driving said table along `said base, said means including areversible motor; a 4first motor control circuit operative to drive4said motor and said tabie in one direction; a second motor controlcircuit operative to drive said mtor and said table in theoppositedirection; a limitsswitch in said first circuit actuated by said tableand connected to means operative to transfer motor control from saidfirst circuit to said second circuit; and a limit switch in said secondcircuit actuated by said table and connected to means operative totransfer motor control back to said first circuit; and a second limitswitch in said first circuit actuated by said table and operative toterminate table movement.

12. In a finishing machine, the improvement comprising in combination: abase; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a first motor control circuit, having a first normallyopen element of a manually actuated switch, and operative to drive saidmotor and said table in one direction; a second motor control circuit,having a second normally open element of said manually operated switch,and operative to drive said motor and said table in the oppositedirection; and a limit switch in each of said'circuits actuated bymovement of said table and connected to means operative to transfermotor control to the other of said circuits.

13. In la finishing machine, the improvement comprising in combination:a base; a workpiece supporting table movably carried by said base; meansfor driving said table along said base, said means including areversible motor; a pair of first motor control circuits, having acommon limit switch actuated by movement of said table and operative todrive said motor and said table in one direction; a second pair of motorcontrol circuits, having a common limit switch actuated by movementof'said table and operative to drive said motor and said table in theopposite direction; a selector switch operative to select one of saidfirst and one of said second circuits, each being adapted for manualoperation, or the other of said control circuits, being each adapted for:automatic operation; and said limit switches being connected to meansoperative to transfer motor control from either of said selectedcircuits to the other of said selected circuits for each position ofsaid selector switch.

14. In a finishing machine having a finishing element, the improvementcomprising in combination: a base, a workpiece supporting table movablycarried by said base adjacentto the finishing element; means for drivingsaid table with respect to the finishing element in a path along saidbase, said means including a reversible motor; means including a selfreturning actuator for verticallypositioning the finishing element withrespect to said path of said table; a first motor control circuitoperative to drive said motor and said table in one direction; a secondmotor control circuit operative to drive said motor and said table inthe opposite direction; and an actuator control cricuit operative toposition the finishing element; said circiuts being interconnected sothat said actuator control circuit can effect positioning of thefinishing element toward the workpiece only when said' motor is drivingin said one direction, and away from the workpiece only when said motoris driving in said opposite direction.

15. In a finishing machine having a finishing element, the improvementcomprising in combination: a base, a workpiece supporting table movablycarried by said base `adjacent to the finishing element; means fordriving said table with respect to the finishing element in a path alongsaid base, said means including a reversible motor; means including aself returning actuator for vertically positioning the finishing elementwith respect to said path of said table; a first motor relay adaptedwhen closed to drive said motor and hence said table in a firstdirection; asecond motor relay adapted when closed to drive said motorand hence said table in an opposite direction; an actuator relay adaptedwhen closed toV position the finishing element toward the workpiece; amain electrical supply line and a return line; a first control circuit,responsive to movement of said table, connected across said lines foroperating said rst control relay; a second control circuit, responsiveto movement of said table, connected across said lines for operatingsaid second control relay; an actuator control circuit, responsive tomovement of said-table, connected across said lines for operating saidactuator relay, said actuator circuit including a pair of normally opencontacts of said first control relay so that said actuator relay can beenergized only when said motor is driving in said one direction; and aholding circuit bypassing said normally open contacts and responsive totable movement in said opposite direction so that said actuator relaycan be de-energized only when said motor is driving in said oppositedirection.

16. In a finishing machine having a finishing element, the improvementcomprising in combination: a base, a workpiece supporting table movablycarried by said base adjacent to the finishing element; means fordriving said table with respect to the finishing element in a path alongsaid base, said means including a reversible motor; means including aself returning actuator for vertically positioning the finishing elementwith respect to said path of said table; a first motor relay adaptedwhen closed to drive said motor and hence said table in a firstdirection; a second motor relay adapted when closed to drive said motorand hence said table in an opposite direction; an actuator relay adaptedwhen closed to position the finishing element toward the workpiece; amain electrical supply line and a return line; a first control circuit,responsive to movement of said table, connected across said lines foroperating said first control relay; a second control circuit, responsiveto movement of said table, connected across said lines for operatingsaid second control relay; an actuator control circuit, including inseries a normally open element of a momentary switch responsive to tablemovement, a pair of normally open contacts of said first control relay,and the coil of said actuator relay, connected across said lines so thatsaid actuator relay can be energized only when said motor is driving insaid one direction; and a holding circuit, including in series anormally closed element of said momentary switch and a pair of' normallyopen contacts of said actuator relay connected in series with said coilbut bypassing the remainder of said actuator control circuit, and a pairof normally closed contacts of said second control relay bypassing saidnormally closed element, so that said actuator relay can be de-energizedonly when said motor is driving in said opposite direction.

17. In a finishing machine having a pair of spaced finishing elements,the improvement comprising in combination: a base; a workpiecesupporting table movably carried by said base intermediate and adjacentto the finishing elements; means for driving said table with respect tothe finishing elements in a path along said base,y

said means including a reversible motor; a pair of means each includinga self returning actuator for one of thel finishing elements, each meansbeing operative to posi-l tion said one of the finishing elements withrespect to said path of said table; a first motor control circuitoperative' to drive said motor and said table in one direction; a secondmotor control circuit operative to drive said motor.v and said table inthe opposite direction; an actuator con-y trol circuit for each of saidactuators, each actuator con` trol circuit being operative to positionthe corresponding finishing element; each of said actuator circuitsbeing interconnected with both of Vsaid motor control circuits so thatone of said actuator control circuits can effect positioning of itsfinishing element toward the workpiece only when said motor is drivingin said one direction, and awayfrom the workpiece only when said motoris driving in said opposite direction, and so that the other of said actuator control circuits can effect positioning of the other finishingelement away from the workpiece only when said motor is driving in saidone direction, and toward the workpiece only when said motor is drivingin said opposite direction.

18. A nishing machine including in combination: ay

base; a reciprocable workpiece supporting table movably carried by saidbase along a path; a pair of finishing elements, one disposed at eachend of said path adjacent to said path; means for reciprccably drivingsaid table with respect to said finishing elements; means forindividually reciprocating said finishing elements transversely to saidpath; and means responsive to table movement for coordinating operationof said table driving means and said element reciprocating means.

19. A finishing machine including in combination: a base; a reciprocableworkpiece supporting table movably carried by said base along a path; apair of pivotally supported arms, one disposed at each end of said pathadjacent to said path; a finishing element secured to each of said arms;each of said arms having a fluid actuator operatively coupled theretowhereby said finishing elements may be moved individually toward andaway from said table path; means for reciprocably driving said tablewith respect to said finishing elements; and means responsive to tablemovement for coordinating operation of said actuators with said tabledriving means.

20. In a finishing machine for the dividing rib of a divided sink, theimprovement comprising in combination: a base; a reciprocablesink-supporting table movably carried by -said base along a path andadapted to support the sink with the dividing rib thereof disposedparallel to said path; a pair of finishing elements, one disposed ateach end of said path adjacent to said path, each rotatable about anaxis parallel to said path, one of said elements being laterallypositionable for engagement with one side of the rib, and the other ofsaid elements 18 being laterally positionable for engagement with theopposite side of the rib; and means for reciprocably driving said tablefor moving the sink rib along each of said nishing elements.

21. A finishing machine including in combination: a base; a reciprocableworkpiece supporting table movably carried by said base along a path; apair of finishing elements, one disposed at each end of said pathadjacent to said path; means for reciprocably driving said table withrespect to said finishing elements; means for individually reciprocatingsaid finishing elements transversely to said path; a coordinatingcircuit including a group of five momentary switches carried by saidbase in spaced relation to each other along said path and eachindividually responsive to movement of said table; the endmost of saidswitches each being operative to effect reversal of said driving means,the middle one of said switches being operative to stop said drivingmeans only when the table is moving in one of its two directions, andthe other two switches each being respectively operative to effectreciprocation of one of said finishing elements toward said path whensaid table is moving toward the corresponding endmost switch, and toeffect reciprocation of said one finishing element away from said pathwhen said table is moving away from the corresponding endmost switch.

References Cited in the file of this patent UNITED STATES PATENTS

